From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2EB33C433EF for ; Tue, 8 Mar 2022 17:59:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=L+QUk6j6QbCySvQNv5/yZXH7AkUXekZxQ9vwY/0hH4s=; b=rztKQc4ukC7BoI 0uyPwUpaSdNx7IqFrW2C4d7KrS9HrRJCMIKVArmR9JPxtKkJDo3QsX0TBIn9Tzfz8VLPiACITDku5 nl3CV+7A5HwsC+rMdtMVq5Z/oHTlpzQksoFnZ5xIlh2LCiVzjk96Fh6e27riGiXiPxTnmJCF6UbYb gb64NpAewYxukDzT101m4gwr26NjTZLvsP17xGVJbNM+d+nPEaFVXvwD8+JGNSaqI/42gy7P43NTE dzVZgDCsQMKbi0FOuLEz4F3YaW3QMotM4crrZQjKJjUtvA29knRC6ZoF97BW1vCOZDctVtNRXIxhP TaMjsS1FTE2qmCZ45sBg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRe5r-005gVY-Gg; Tue, 08 Mar 2022 17:57:55 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nRe5n-005gUj-EM for linux-arm-kernel@lists.infradead.org; Tue, 08 Mar 2022 17:57:52 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=PpZLv3q78rxILUILZuIRhQ5QDV8O6Gqy6pmSYzlsrRY=; b=mxK5QU6CKfNncBpjYK+OK0X9KT ed6Og1kPo+JglHMfFmJJGoWoqGXYOWpFbz13pq03Nb3ILCeKPWlFfV2aw1rN4jCgUY9RzjcC/Yvg+ m+7+pP/ggxUA9wm42m79JuTCRsW/NrLK2FyBNQgFKvc2MlrdolV/5bPlBEMsgVrxzvg+U7hWX3OPR Q0ObX69IoWBgDtOnlI20vgoh2F5feKOuFxx02zXBnYbojdBLVL2yiLlu7zDefhg+BGcNP5WsR/EA6 M1KJufsxzSN2XjdlcqO4h0iG3LI5iXr1RZd7yNiMZeJhR8mrQ0zMgMLp9Hultkxnd4raSXtFcjDQA x8A1dmXA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57722) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nRe5i-0000iC-Mm; Tue, 08 Mar 2022 17:57:46 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nRe5i-00074Z-1a; Tue, 08 Mar 2022 17:57:46 +0000 Date: Tue, 8 Mar 2022 17:57:46 +0000 From: "Russell King (Oracle)" To: Robin Murphy Cc: Arnd Bergmann , Marc Zyngier , Rongwei Wang , Catalin Marinas , Will Deacon , joey.gouly@arm.com, Mark Rutland , Andrew Morton , Linux ARM , Linux Kernel Mailing List Subject: Re: [PATCH RFC] arm64: improve display about CPU architecture in cpuinfo Message-ID: References: <20220307030417.22974-1-rongwei.wang@linux.alibaba.com> <87h78a178u.wl-maz@kernel.org> <87bkyi0x53.wl-maz@kernel.org> <1b94af8b-a294-5765-4e1e-896f70db621f@arm.com> <9296f97c-f894-001c-53e6-41bbfe36ce71@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <9296f97c-f894-001c-53e6-41bbfe36ce71@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220308_095751_507438_2EBF909D X-CRM114-Status: GOOD ( 24.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Mar 07, 2022 at 08:05:06PM +0000, Robin Murphy wrote: > On 2022-03-07 19:30, Arnd Bergmann wrote: > > On Mon, Mar 7, 2022 at 5:48 PM Robin Murphy wrote: > > > > > And arguably it's not even too late, because 10 years ago this *did* say > > > "AArch64". I don't remember all the exact details behind commit > > > 44b82b7700d0 ("arm64: Fix up /proc/cpuinfo") - this just tickled enough > > > of a memory to go and look up the git history - but I don't think we > > > changed any of those fields without a real reason. > > > > > > > The patch description does state that this was done for compatibility with > > 32-bit architectures, which does make some sense. I suppose for similar > > reasons, the arch/arm/ version of /proc/cpuinfo is now stuck at > > 'CPU architecture: 7', even for ARMv8 or higher in aarch32 mode. > > > > The part that I find more annoying is how we leave out the one bit > > of information that people are generally looking for in /proc/cpuinfo: > > the name of the processor. Even though we already know the > > exact processor type in order to handle the CPU errata, this is > > always "model name\t: ARMv7 Processor rev %d (v7l)" on 32-bit, > > and "model name\t: ARMv8 Processor rev %d (%s)" on 64-bit, > > with the revision being the least important bit of information here... > > Eh, it's hardly impossible to recompose a MIDR value from the implementer, > part, variant and revision fields if one actually needs to. Maybe we could > null-terminate the raw MIDR value and print it as a string of > largely-unprintable characters in the "model name" field... I guess that > might satisfy the crowd who want parity* with x86 CPUID, at least :) Actually, it is impossible to do it reliably. I won't expand on this, except what I said in my other reply - there are cases where the MIDR value is not unique. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel